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I assume you are leaning towards Caspian gull here. I can see how one would lean towards caspian but in my opinion the bill is too stubby and herring gull like for it to be a caspian. The wings are not attenuated enough, once again they seem to fit herring gull. Also, the dark eye is not a reliable feauture to go by and some herring gulls can show this feautue. Anyone please feel free to correct me here.

I assume you are leaning towards Caspian gull here. I can see how one would lean towards caspian but in my opinion the bill is too stubby and herring gull like for it to be a caspian. The wings are not attenuated enough, once again they seem to fit herring gull. Also, the dark eye is not a reliable feauture to go by and some herring gulls can show this feautue. Anyone please feel free to correct me here.

Yes, I can see what you mean about the wings.

I didn't want to say what I was leaning towards, because this tends to attract people who seem to take pleasure in pissing on your chips.

We did think we were in with a shout of Caspian Gull, based on the eye, the white head and the plumage, which you can't see that well in my digiscoped picture.

What interested us about this bird was that its head was very white (with a slight light brown streaking to the back of the neck) combined with the black eye. The bill, although not especially long, looked parralel sided. It stood out like a sore thumb next to the other Herrings.

The gulls on this site seem to all have streaking on the head, which our bird lacked.

I think the problem, Kay, is that the pictures aren't great and one might assume that any streaking on the head has been lost due to the picture being over-exposed. I didn't see any streaking on the head in the field.

The gull has more of Yellow-legged Gull structure than Caspian (note the Caspian feature - 'bump' behind the legs) Flatish back, large unmarked head and small looking dark eye might point towards YLG or CG for that matter. The almost unmarked upperparts and relatively large grey area on median covert and no white tips on the primaries seems to advanced for a 2cy Herring, in all, body looks like a 3cy Herring while primaries looks 2cy. Huge variation must be considered, - look at Reg,s linked Herrings, the standing gull looks like a type 3cy or older?, with well marked white tips to primaries and a large mirror on p10, while the other Herring looks like a 2cy.
Some Herring can be more advanced than otheres and have dark small looking eyes as 2cy (usually pale eyes from 2cy), and adult.

No, not at all, but Stubber’s Green has gained a reputation for attracting Caspian Gulls on a regular basis and if you went in the hope of seeing one, I can understand how this bird would have attracted your attention. From the two photographs posted here, it still appears to be a Herring Gull. All large gulls can be extremely variable in plumage and there will always be a few that stand out, but for that reason alone.

I realize that a hybrid can never be fully excluded, but I actually see little wrong for this to be a 2w Caspian Gull. The bill could easily fit a (large) male and the underwing is well within the variation.
It is definitely not a Herring Gull.
The thumbnail posted above (message #3) shows two American Herring Gulls, so is not really relevant here.

Hi there,
I would like to know what proportion of 2nd-w Caspian Gulls lack a small white mirror on P10? In my opinion, the 2nd-w on the Chasewater website (URL provided in post no. 18) seems to be the same bird as in the original pics (based on the extent of moult being the same, as far as can be made out), and, while it does look a lot better for Caspian in those higher-quality shots, I can't help but note the lack of a white mirror on P10, and was wondering whether this would be within the range of variation for 'pure' Caspian, or if this would indicate Herring Gull genes in there somewhere?
It does look rather good for Caspian otherwise, with the proviso that I have only seen birds of this age in photos.

Could be a hybrid Caspian x Herring as suggested but a pure Herring - perhaps not -although structurally it would fit one. However, I don´t see a pure Caspian structurally (good fit on plumage for 2cy type Caspian), large head, wrong bill structure, especially to short-billed if a male, short primary projection and rather short legs, although some Caspian looks shorter-legged - both in the field and in images. 'Bump' behind the legs Caspian feature alright.

Harry - I can´t say anything about the number of 2-3cy Caspians lacking the mirroron p10, but it is a variable character, most of which I have seen have had a mirror, from very small - hardly noticeable, to quite large, clearly visible.
No mirror on this one:

I realize that a hybrid can never be fully excluded, but I actually see little wrong for this to be a 2w Caspian Gull. The bill could easily fit a (large) male and the underwing is well within the variation.
It is definitely not a Herring Gull.
The thumbnail posted above (message #3) shows two American Herring Gulls, so is not really relevant here.

Yes; and, importantly, solid black tail spots apparently lacking the jagged edges and/or thin, dirty barring usually seen in 3w European Herring Gull. Add to this the very pale iris and the extensively brown-washed hindneck and belly.